[jgtrosh]

I agree it's awkward, but not because of M_PI being non-standard. If history had lead to pi being defined in standard C, this code would still have been interesting. The title is awkward because it talks more about M_PI than about the content of the article.

[quietbritishjim]

I agree that the code is interesting. It was specifically the HN title I was talking about, which is not even the title of the original article. Sorry if I wasn't clear. Anyway, it's been updated now.